The Online Publication and Book Series Dedicated to the Thermal Management of Electronics

Qpedia Thermal eMagazine was launched in 2007 as a monthly newsletter focused on the thermal management of electronics. Now in its 9th year of publication, Qpedia is a highly respected monthly magazine that is distributed at no charge to over 18,000 engineers. Written and published by the engineers of Advanced Thermal Solutions, Inc., Qpedia is a technical resource to help the engineering community solve the most challenging thermal problems. Each issue provides practical approaches to thermal management challenges and explains the new technologies for successfully cooling today and tomorrow’s hot-running electronics.

Table of Contents -
May 2010

The creation of controlled time-variant disturbances, even in some fluid-dynamically polluted flows, will result in an increase in the convection heat transfer coefficient from a solid wall. For example, recent developments on the use of piezoelectric flappers create an unsteady, oscillating airflow scheme which yields good heat transfer results.

Modeling the Transient Thermal Response of Single- and Multi-Chip Packages

Regardless of its complexity, the thermal impedance of a semiconductor package can be modeled by combining two basic elements: thermal resistance and thermal capacitance. The simplest example is a die that is directly exposed to ambient. In switching mode, two scenarios must be evaluated.

The Effects of Leakage Current in Electronics Thermal Management

High temperatures and very small transistor sizes can result in leakage current situations which also increase heat flux. As circuit sizes get smaller, the space between the wires also shrinks. This space is supposed to be an insulator, but as the distance between two wires gets smaller, current begins to leak across the thinner insulation barrier.

Understanding and Optimizing Thermal Vias

To maintain acceptable junction temperatures, along with reducing junction-to-ambient resistance through the component case, it is often necessary to dissipate some device power through the board. A standard PCB is often designed with electrical performance in mind; however, using thermal vias to improve thermal performance should not be overlooked.